Theatrical Carpentry Handbook

Transcription

1 Theatrical Carpentry Handbook 2011

2 Contents THEATER SPACES... 1 Stage types:... 1 Proscenium stage:... 1 Thrust Stage:... 1 End Stage:... 2 Arena Stage:... 2 Flexible Stage:... 2 Sports Arena:... 2 FLY SYSTEMS... 3 The Line Set:... 3 Line Set functions:... 3 Drapery and track line set:... 4 Scenery line set:... 4 Electrical line set:... 4 Fire Safety curtain:... 4 Fly System Types... 5 Hemp Rigging System:... 5 Counterweight Rigging System:... 6 Double Purchase Counterweight Systems:... 7 Automated Rigging Systems:... 7 Fly Systems Components:... 8 Battens:... 8 Standard Pipe Batten:... 9 Truss Batten:... 9 Electric Batten:... 9 Lines: Lift lines: Operating lines: Line Control: Belaying pins: Knots: Rope locks:... 11

3 Swage: Trim chains, shackles, turnbuckles, and pipe clamps: Blocks: Loft Block: Head Blocks: Mule Blocks: Tension Blocks: Counterweights: Arbors: Hoists: Drum hoists: Line shaft hoist: Point hoists: Chain hoists: Infrastructure: Fly loft: Grid deck: Rope line (hemp) head block well: Loft block wells: Loading bridge: Fly gallery: Pin rail: Locking rail: Arbor pit: Operation: SOFTGOODS Legs: Tormentors: Borders: Teaser: Portal: Velour: Duvetine: Corduroy:... 23

4 Construction of Curtains: Guillotine Curtain: Travelers or draw curtains: Braille curtain, or Austrian drape: Tab or Tableau curtains: Contour or profile curtains: Fullness: Other Softgoods Cycloramas or cycs: Transparency: Drops, or backdrops: Full drop: Cut drop: Roll drop: Tripped drops: SCENE SHOP Flat Assembly: Hollywood or TV flat: Metal flats: Platforms: Legging platforms: Parallels: Stairs and Stairways: Laying out Stairs: Joints: Butt joint: Lap joints: Half laps: Miter joint: Scarf joints: Dado and rabbet joints: Mortise and tenon joint: Dowel joints: Spline Joint:... 35

5 Biscuit joint: Dovetail joint: Fasteners: Common nails: Box nails: Sinker or coated nails: Finishing or casing nails: Duplex nails: Staples: Bolts: Craft Development Committee... 38

6 THEATER SPACES Theater: a space where a performance takes place, a large machine in the form of a building specialized for presenting performances. Stage types: Proscenium stage: A proscenium Stage is what we usually think of as a "theater". Its primary feature is the Proscenium, a "picture frame" placed around the front of the playing area of an end stage. The frame is the Proscenium; the wings are spaces on either side, extending off stage. Scenery surrounds the acting area on all sides except the side towards the audience, who watch the play through the frame opening. "Backstage" is any space around the acting area out of sight of the audience. Stage directions are given from the viewpoint of an actor center stage facing the audience. Stage Left is the actors left, Stage Right to the actors right. Downstage is towards the audience. Upstage is towards the back wall of the stage. The Plaster Line (PL) is a line running from the back of one side of the proscenium arch to the other side of the proscenium arch. The Center Line (CL) runs upstage/downstage half way between prosceniums and perpendicular to the Plaster Line. Everything downstage of the Plaster line is called Front of House (FOH). Occasionally it is also called "Ante-proscenium" which means before the proscenium. Anything the audience can see on the stage is on-stage". Anything on the stage but out of the audience view is "off-stage" or "backstage". The floor is called the "deck". The part of the stage in front of the Proscenium is the "Apron", or sometimes the "Thrust". The audience seating is the "Auditorium" or the "House". Thrust Stage: A stage surrounded by audience on three (3) sides. The fourth (4th) side serves as the background. In a typical modern arrangement: the stage is often a square or rectangle playing area, usually raised, surrounded by raked seating. Theatrical Carpentry pg. 1

7 THEATER SPACES End Stage: A Thrust stage extended wall to wall, like a thrust stage with audience on just one side, the front. "Backstage" is behind the background wall. There is no real wingspace to the sides, although there may be entrances there. An example of a modern End Stage is a music hall, where the background wall surround the playing space on three (3) sides. Like a Thrust stage the scenery is primarily in the background. Arena Stage: A central stage surrounded by audience on all sides. The stage are is often raised to improve sight lines. Flexible Stage: Sometimes called a "Black Box" theater, they are often big empty boxes painted black inside. Stage and seating not fixed. Instead, each can be altered to suit the needs of the play or the whim of the director. Sports Arena: Sport arenas often serve as venues for Music Concerts. In form they resemble very large arena stages, but with a rectangular floorplan. When used for concert, a temporary stage is up as an end stage on one end of the floor, and the rest of the floor and the stands become the audience. Arenas have their own terminology. The stage is usually set up at the loading dock end of the building for ease of setup. Opposite the stage is the Front of House (FOH), sometimes called "Sound World", as the mixing consoles are located here. Standard stage directions are usually used (Stage Right, Stage Left, Downstage, Upstage, etc.). The Monitor mixer often go SL and lighting dimmers go SR in Dimmer Beach. Seating is located on the main floor between the Stage and FOH, and also in the bleachers. Audience entrances from the "concourse" (lobby areas) into the seating bowl are called VOMs short for Vomitories, the old Roman name for such entrances. Theatrical Carpentry pg. 2

8 FLY SYSTEMS A fly system, flying system, or theatrical rigging system is a system of lines (e.g. ropes), blocks (pulleys), counterweights and related devices within a theater that enable a stage crew to quickly, quietly and safely fly (hoist) components such as curtains, lights, scenery, stage effects and, sometimes, people (e.g. Peter Pan). Systems are typically designed to fly components between clear view of the audience and out of view, into the large opening, fly loft above the stage. Fly systems are often used in conjunction with other theater systems, such as Scenery wagons, stage lifts, and stage turntables, to physically manipulate the scenery. theatrical rigging is most prevalent in proscenium theaters with stage houses designed specifically to handle the significant dead and live loads associated with a fly system. Building, occupational safety, and fire codes limit the types and quantity of rigging permitted in a theater based on stage configuration, Theatrical rigging standards are developed and maintained by organizations such as USITT and ESTA. The Line Set: The line set is the fundamental machine of a typical fly system. The function of a typical line set is to fly (raise and lower) a slender beam (typically a steel pipe) known as a batten by hoisting it with lift lines (typically synthetic rope or steel cable). By hanging scenery, lighting, or other equipment to a batten, they in turn may also be flown. A batten is said to be "flying in" when it is being lowered towards the stage, and "flying out" when it is being raised into the "fly space". Battens may be just a few feet in length or may extend from one wing (side) of the stage to the other. A batten is suspended from above by at least two (2) lift lines, but long battens may require six (6) or more lift lines. Line Set functions: Line sets are typically general purpose in function, meaning they can perform any number of functions which vary depending upon the requirements of a particular theater production. For example, a general purpose line set can usually be quickly transformed into a drapery or scenery line set, but converting a general purpose line set into a electrical line set is more involved. When a line set has a predetermined, relatively permanent function it is known as a "dedicated line set". Theatrical Carpentry pg. 3

9 FLY SYSTEMS Drapery and track line set: Line sets often suspend theater drapes and stage curtains such as "travelers", "teaser, (a.k.a. borders), legs, cycs, scrims and tabs, as well as associated tracks, in order to mask the stage and provide backdrops. Line sets are sometimes dedicated to particular draperies, such as the main (grand) curtain and main border (valance) that mask the proscenium opening, but drapery locations can often vary. Scenery line set: In many stage productions, theatrical scenery is mounted to line sets in order to be flown in and out so as to quickly change set pieces during the course of a performance. For example, painted soft and hard flats (e.g. muslin drops) are used to depict settings. Also, three dimensional sets (e.g. box sets) may be flown. Electrical line set: Electrical line sets commonly called "electrics" are used to suspend and control lighting instruments and in many cases microphones and special effects equipment as well. Electrics may be temporarily "wired" with drop boxes (electrical boxes with outlets) or multicable "fanouts" dropped from the grid or draped from a fly gallery, or permanently wired with "connector strips" (specialized electrical raceway). There are normally at least three (3) electrical line sets provided above the stage, with one just upstage of the proscenium wall, one mid-stage, and one just downstage of the cyc. Additional electrics are typically desirable. Fire Safety curtain: A permanently installed "fire curtain" line set, though not used for productions, it is a typical element of a theatrical rigging system installation. Building and fire codes typically require that either a fire curtain or "water deluge" system be installed to separate an audience from the stage in the event of a fire. Theatrical Carpentry pg. 4

10 FLY SYSTEMS Fly System Types Fly systems are broadly categorized as "manual" or "automated" (motorized). Manual fly systems are more specifically categorized as "hemp" (a.k.a. rope line) or "counterweight" systems. Hemp Rigging System: A hemp fly system, so named for the manila hemp rope that was once common in theatrical rigging, it is both the oldest and simplest type of fly system. Hemp systems are also known as "rope line" systems or simply as "rope" systems. Stage rigging techniques draw largely from ship rigging. That origin is most obvious with hemp rigging, which uses closely related technology and terminology. To this day, the stage is referred to as a "deck" in the manner of a ship's deck. Other expressions that overlap the nautical and theatrical rigging words include: batten, belay, block, bo'sun, cleat, crew, clew, hitch, lanyard, pinrail, purchase, trapeze and trim. In a typical hemp system line set, the lift lines and hand (operating) lines are one in the same. The lift lines run from the batten up to "loft blocks", across the stage to a "head block" and back down to a "pin rail", where the lines are tied off, "belayed" with "belaying pins". A "trim clamp" (a.k.a. knuckle buster) is used to attach the sand bags to the lift lines to balance the load placed on the batten. The sandbags are usually filled to weigh a few pounds less than the load, making the line set batten-heavy (load-heavy) so it will fly in under its own weight when the lift lines are let out. Another hand line, known as a "jack line" may be used to lift the sandbags if they are heavier than the batten load. The jack line, which runs up to a loft block and back down to the trim clamp, is tied off to a belaying pin adjacent to the one used for the line sets lift line, either at the same or secondary, pin rail. Pulling on the hand lines of a hemp set flies a line set out. Pulling on the jack line flies a line set in. Hemp systems can be easily configured for spot rigging, where lift lines must be frequently relocated. They are much less expensive and easier to install than counterweight fly systems, though somewhat more difficult to operate. Theatrical Carpentry pg. 5

11 FLY SYSTEMS Counterweight Rigging System: Developed in the first half of the 20th century, counterweight rigging systems are the most common fly systems in performing arts facilities today. In a typical counterweight fly system, an " arbor" (carriage) is employed to balance the weight of the batten and attached loads to be flown above the stage. The arbor, which carries a variable number of metal "counterweights" moves up and down vertical tracks alongside an offstage wall. In some lower capacity fly systems, cable guide wires are used instead of tracks to guide the arbors and limit their horizontal play during vertical travel. The top of the arbor is permanently suspended by several wire rope "lift lines" made of galvanized steel aircraft cable. The lift lines run from the top of the arbor up to the top of the fly tower, around the "head block", across the stage to evenly spaced "loft blocks", then down terminating at the batten, a load-bearing pipe that spans much of the width of the stage. If the loft blocks are mounted to the "grid deck", at the "loft block wells", the system is called a "grid mount", or "upright" counterweight rigging system. If the loft blocks are mounted to roof beams, the system is called an "under-hung" counterweight rigging system. Under-hung systems have the advantage of maintaining a clear grid deck surface for spot rigging and facilitating crew movement across the grid. The arbor's vertical position is controlled by the means of a rope known as the "operating line", "hand line", or "purchase line":. The operating line forms a loop by running from the bottom of the arbor down to and around the "tension block", through the "rope lock", up and over the "head block" and back down (alongside the lift lines), where it terminates at the top of the arbor. The head and tension blocks are located above and below the full extent of the arbor's travel (movement), respectively, thereby enabling an operator to pull the operating line up or down to move the arbor. When the arbor is raised via the operating line, the lift lines slacken, which causes the batten to lower under its own weight (and the weight of its load if any). Conversely, when the arbor is lowered, the lift lines increase in tension, which in turn causes the batten to rise. The combined weight of the arbor and its counterweights initially matches that of the batten, so that when the batten is not being raised or lowered, it will tend to remain motionless at any arbitrary elevation above the stage. As more weight is added to the batten ( in the form of curtains, scenery, lighting equipment, and rigging hardware), the system is rebalanced by adding more counterweights to the arbor. When the system is properly balanced, an unassisted operator ("flyman") can lift the batten and its arbitrarily heavy load from the stage, completely Theatrical Carpentry pg. 6

12 FLY SYSTEMS above the proscenium and out of view from the house, sometimes to heights in excess of seventy (70) feet. Double Purchase Counterweight Systems: "Double purchase counterweight systems" are sometimes used where the vertical travel of the counterweight arbor would be inadequate due to limited fly space or limited off-stage space at the stage deck. In systems of this type, the operating and lift lines are "double purchased" so that the batten can travel twice the distance of the arbor. In other words, for every foot of arbor travel, the batten travels two (2) feet. Often times this means the arbors remain well clear of the stage deck below, leaving the otherwise occupied wing space usable for the cast and crew. In a conventional counterweight system the operating and lift lines terminate at the top of the arbor after passing over the head block. In a double purchase system, however, after passing over the head block the operating and lift lines pass through another block mounted to the top of the arbor before rising back up and terminating below the head block. In addition, the opposite end of a double-purchase operating line terminates at the "fly gallery", off stage wall, or stage deck, instead of the underside of the arbor, after passing through a block mounted at the underside of the arbor. The additional blocks result in the arbor moving at half (1/2) the rate of the lift and operating lines. In order to compensate for the reduced arbor travel, the loaded arbors must weigh twice as much as the batten load, resulting in arbors that are twice as long. The additional mass on the arbor increases inertia and the additional blocks increase friction, resulting in line sets that are more difficult to operate. In addition, double-purchase lines sets are also more expensive to install and maintain. For those reasons, double-purchase line sets are generally avoided, or limited to a few sets within a counterweight system, unless space issues preclude the use of a (space for arbor travel. Automated Rigging Systems: Electrical hoists (also referred to as winches) can facilitate coordination with cues, move extremely heavy line-sets, and significantly limit the population of the fly crew. Despite those potential benefits, most hoists can fly line sets at only a fraction of the speed that an experienced flyman can achieve manually. There are two (2) general categories of motorized fly systems, "motor assist" and "dead-haul". "Motor -assist" systems closely resemble standard counterweight fly systems described above, however a drum winch, typically mounted behind the locking rail below the arbor, is used to Theatrical Carpentry pg. 7

13 FLY SYSTEMS drive a steel cable purchase line. The purchase line is still terminated at the top and bottom of the arbor, but a rope lock is not used on the motor-assist line set. Weight on the arbor helps balance the batten load so that the hoist motor size can remain relatively small. It is often feasible to retrofit a standard counterweight line set to become a motor-assist set. "Dead-haul" systems fly the entire load placed on a line set without the assistance of counterweight. Therefore dead-haul motor sizes are relatively large. Hoist (winch) motors are either "fixed speed" or "variable speed". Fixed speed motors are used at heavy-load and/or slow-speed line sets (e.g. electrics and orchestra shell line sets). Variable speed motors are used at line sets requiring dynamic motion that may be viewed by the audience (e.g. drapery and scenery line sets). scenery hoists commonly allow travel at rate of hundreds of feet per second. Digital control systems incorporating computers or programmable logic controllers (PLCs) have become commonplace as well, bringing their advantage of high accuracy, safety, and repeatability to fly systems. Fly Systems Components: Battens: Battens are linear members, typically steel pipe, to which live loads may be attached for flying. Loads mounted to battens include lights, curtains and scenery so they may "travel" vertically, be raised up into fly space (flown out) or lowered near to the stage floor (flown in) by its associated line set. Battens usually stretch the width of the stage, parallel with the proscenium wall, and are maintained level (parallel to the stage deck) regardless of elevation. When a batten is flown all the way out ( close to the grid ) it is at "high trim". When it is flown all the way in (usually about 4' off of the stage deck) it is at "low trim". Loads are attached to the batten in various ways. Most lighting fixtures, for example, utilize a C-clamp to rigidly secure the light onto the batten, in conjunction with a safety cable that is looped around the batten to prevent the light from falling should the C-clamp connection fail. Non traveling curtains (e.g. borders) often employ cloth ties, similar to shoe laces, that are tied onto the batten. Theatrical Carpentry pg. 8

14 FLY SYSTEMS Battens are suspended by evenly spaced lift lines, with "pick points" generally nine (9') to twelve (12') feet on center. The unsupported cantilevered ends of a batten, beyond the last lift line pick points, are generally no longer than three (3') feet unless a "bridle" is used to effectively limit the cantilever. Standard Pipe Batten: Battens were originally made from wood, but have been replaced by steel pipe. In the United States they are typically fabricated from twenty-one (21') foot sections of 1 1/2" nominal diameter, schedule 40, steel pipe that are spliced together (with internal pipe sleeves and bolts) to provide a continuous member that stretches the width of the stage. Standard pipe battens are typically designed to support fifteen (15) to thirty (30) pounds of live load per foot of pipe. Truss Batten: Truss battens, sometimes referred to as a double batten, use a pipe over pipe arrangement (often twelve (12") inch center to center), with vertical struts welded between the upper pipe and lower pipes to provide rigidity. Truss battens generally permit greater loads than a single-pipe batten and may not require as many lift lines due to improved ability to span between lift lines. Truss battens are typically designed to support twenty five (25) to fifty (50) pounds of live load per foot. Electric Batten: An electric batten, a.k.a. "lighting batten", may be a single pipe or truss batten. Electric battens typically incorporate steel straps that are used as brackets for the support of electrical equipment such as "connector strips" (raceways). The same straps supporting electrical equipment may also connect the two (2) pipe arrangement of a truss batten. The center-to-center spacing of electric truss pipe (often from 1'-6" to 2'-6") is typically greater than for a standard truss batten to allow for the proper mounting and focusing of lighting instruments. It is typical for an electric batten to support thousands of pounds of live load. Theatrical Carpentry pg. 9

15 FLY SYSTEMS Lines: Lines are the ropes, cables (wire ropes) and proof coil chains that enable a fly system to function. Steel bands are a relatively new type of line used in "steel band hoists". It is standard practice for overhead rigging lines and hardware to be rated with at least a eight (8) times safety factor to help ensure the protection of the cast and crew. In other words, a line intended to support 100 pounds should have a safe working load of at least 800 pounds. Lift lines: carry and transfer the loads of a fly system to the fly system infrastructure. The lift lines for manual rigging run from the batten up to loft blocks, across the stage to a head block, and down to the counterweight balancing the load on a line set. When running horizontally, between loft blocks and head block, lift lines typically follow a transverse path (side to side) across the stage. Operating lines: also known as "hand lines" or "purchase lines" are what the crew uses to manipulate manual fly systems. Operating lines are connected to sandbags (in a hemp system) or the top and bottom of arbors (in a counterweight system). Operating lines are typically 5/8" or 3/4" in diameter. Lift and operating lines were commonly made of manila hemp. The rope was often simply referred to as "manila". Use of manila had a number of issues. Splinters of fiber could get into hands and eyes. Humidity and temperature changes could significantly affect the length of the rope. Over time the rope slowly rots. Synthetic rope can reduce or eliminate these issues, while providing greater strength by volume. Over time polyester rope became more than manila in hemp systems and for use as the operating lines in counterweight systems. The lift lines of a counterweight rigging system are typically a specific type of steel wire rope known as galvanized aircraft cable (GAC). Oil free 1/4" diameter, 7 x 19 strand, GAC is the most common counterweight system lift line. It has a minimum cable breaking strength of approximately seven thousand (7,000) pounds. Line Control: Load bearing lines must be safely tied off, locked, terminated and/or connected to other rigging components to ensure line control and the safety of a fly system. Various methods are employed. Theatrical Carpentry pg. 10

16 FLY SYSTEMS Belaying pins: are used to "belay", temporarily tie off, the ropes lines of a hemp system. Each belaying pin serves as a anchor to which the loose end of a rope may be quickly secured. A standardized method is used to tie off the rope so that it is subjected from friction from itself as well as from the pin rail, thus ensuring a secure connection that is unlikely to fail. Belaying pins are typically made of hickory wood or steel. Knots: such as the "clove hitch" and "half hitch" are used for rope line terminations. For example hitches are used to terminate hemp lift lines at battens and operating lines at counterweight arbors. Rope locks: are cam-actuated devices through which a counterweight system operating line passes. The adjustable cam or "dog", inside the rope lock constricts and releases the operating line as the flyman lowers and raises a hand lever. Rope locks are mounted in series to the locking rail. A single rope lock can typically secure a static unbalanced load to fifty (50) pounds. Rope locks are not intended to slow a running line. Swage: (compression or nicopress) fittings or "cable clips" are used to terminate counterweight system lift lines, after the cable has been looped around a "thimble". Cable clips terminations maintain less load capacity than swage fittings, typically require three clips, and are greatly reduced in load capacity if the installer happened to "saddle a dead horse". Both swage and cable clip terminations permanently crimp (deform) the wire rope. Trim chains, shackles, turnbuckles, and pipe clamps: typically connect the lift lines of a line set to the batten they. Those connections facilitate minor adjustments to "trim", the effective length of a lift line. By trimming the lift lines, loads are more evenly distributed to them. Turnbuckles are moused (secured against free rotation) to prevent the jaws from slowly unscrewing over time due to vibrations incurred during normal use. Theatrical Carpentry pg. 11

17 FLY SYSTEMS Blocks: A "block" is a pulley used to support and direct lift and operating lines. A block consists of a grooved wheel, known as a "sheave" (pronounced "shiv"), steel side plates, spacers, shaft, flange bearings, mounting angles and clips, etc. Blocks are sized based on anticipated live loads, operating speeds, line type and other factors. Sheaves were traditionally fabricated of cast iron, but steel and nylon sheaves are now common. Blocks are either "upright", when mounted atop a support structure, or "under-hung", when mounted to the underside of a support structure. The side plates of blocks preferably fully cover the profile of (fully enclose) the sheaves to lend the block greater stability and limit the sheave's (and crew's) potential damage from foreign objects. Nevertheless, blocks are available with exposed sheaves. Loft Block: A "Loft block" is an overhead block that supports a single lift line. A loft block supports and redirects a lift line from the batten to the head block of a line set. Under-hung loft blocks typically mount to "loft block beams" (fly loft roof beams). Upright loft blocks typically mount to "loft block wells" (grid-level structural channels). A "spot block" is a readily moveable loft block for mounting anywhere on the grid deck for support rigging. The diameter of a loft block sheave for galvanized aircraft cable is typically at least 32 times the diameter of the cable. For example 8" loft blocks are typically used with 1/4" GAC, but 12" blocks may be used to facilitate flying heavier line sets (e.g. electrics). Loft blocks may be equipped with "idler pulleys" or "sag bars" to limit the sag of horizontally running lift lines on under-hung systems. In under-hung counterweight systems that use "upright head blocks" the series of loft blocks immediately following the head blocks are typically multi-line loft blocks instead of single-line to account for built-in vertical misalignment between head blocks and loft blocks. Head Blocks: are overhead multi-line blocks used for the lift lines and operating lines. Head blocks support and redirect all the lift lines from loft blocks to sand bags (of a hemp set), counterweight arbor (of a counterweight set) or hoist (or an automated line set). Theatrical Carpentry pg. 12

18 FLY SYSTEMS Rope line (hemp) head blocks are typically upright blocks that mount the "rope line head block well" channels at the grid level. In a counterweight rigging system the head block sheave is grooved for both the steel cable lift lines and an operating line, with the groove for the operating line provided at the middle of the multi-grooved sheave, between the lift lines. Counterweight head blocks mount atop or at the underside of the head block beam, depending on the beam's vertical position. The diameter of a head block sheave used for galvanized aircraft cable is typically at least 48 times the diameter of the cable. For example 12" head blocks are typically used with 1/4" GAC, but 16" blocks may be used to facilitate flying heavier line sets (e.g. electrics). Mule Blocks: Lift lines sometimes require diversion to avoid obstacles, support non-linear loads and battens, deal with excessive "fleet angles", or be reoriented from the typical transverse path across the stage (e.g. for tab and light ladder line sets). "Mule blocks" are single or multi-line blocks able to divert the path of those lines. Mule blocks may be permanently installed as part of counterweight rigging systems, or used for spot rigging, where they are often equipped with swivel-pivots to divert lines across a large range of angles. Tension Blocks: are single-sheave blocks located at the lower end of the arbor guide track, beneath the arbor. The operating line is reeved through the tension block from the bottom of the arbor through the rope lock. Tension blocks typically ride vertically along the arbor guide system track, instead of being fixed, to allow for variation in the length of the operating line. Theatrical Carpentry pg. 13

19 FLY SYSTEMS Counterweights: Counterweights are one of more sandbags (in hemp systems) or metal bricks (in counterweight systems) used to balance the line set loads. The term "counterweight" is commonly used to refer specifically to metal counterweight bricks. Metal counterweights are made of lead, pig iron, or flame-cut steel. Flame cut steel bricks are most common. In any particular fly system all weights typically share a common, standardized footprint that matches the system's arbors and corresponds with line set spacing. Counterweight systems are most often designed to used either 4 or 6-inch (150 mm) wide weights. Weights vary in thickness, typically in half-inch increments ranging from 1/2 to 2 inches (51 mm), with each thickness corresponding to a different mass. 1" thick weights are most common. Counterweights are sometimes known as "bricks" or simply "steel". Often a rigging worker will be asked to load a number of inches of steel, which correlates to a specific mass. Weights are usually loaded from the loading bridge, but can also be loaded from the fly gallery or stage deck in some circumstances. When viewed from the top, metal counterweight is basically rectangular, typically with 45- degree angle chamfers cut at two opposing corners. A slot is cut into each end of the weight so as to enable the weight to straddle, and be laterally secured by, the arbor rods. In order to facilitate removal of weights with angle cuts, it is customary to stack the weights in alternating orientations so that the square corners of any weight will be aligned with the angled corners of adjacent weights. This simplifies removal because the protruding square corners of the topmost weight effectively serve as "handles" that can be easily gripped, even with gloved hands. It is customary to apply paint (typically yellow) or colored tape to the weights that counterbalance the batten (pipe) to indicate that they should not be removed from the arbor. As an additional precaution, they may be strapped in with steel strapping. When a dedicated line set carries a permanent load (e.g. main drape, orchestra cloud, etc) the counterweight balancing the additional load may be treated in a similar fashion. Theatrical Carpentry pg. 14

20 FLY SYSTEMS Arbors: A "counterweight arbor" is a sturdy mechanical assembly that serves as a carriage for counterweights. In its simplest form, an arbor consists of two horizontal steel plates, a "top plate" and "bottom plate", tied together by two vertical steel "connecting rods ". Counterweights are stacked as required on the arbor's bottom plate to balance the line set load, with the weights held in place by connecting rods. A flat "tie bar" at the rear of the arbor also connects the top and bottom plates. "Guide shoes" at the top and bottom of the tie bar guide the arbor along tracks mounted to the side stage wall. UHMWPE pads on the guide shoes limit friction between guide shoe and track as the arbor travels. "Spreader plates" are thin steel plates with holes through which the arbor connecting rods pass. Spreader plates are lowered onto the counterweights in a distributed fashion as the counterweight stack is being built. Typically one spreader plate is placed on top of every two feet of counterweights and spreader plates and secured in a place with a thumbscrew. Spreader plates serve to maintain consistent spacing between the arbor rods to ensure reliable containment of the counterweights under normal operating conditions. Also, in the event of a "runaway" (loss of control of an unbalanced lineset), the spreader plates will prevent the arbor rods from bending outward, and thus releasing the counterweights upon arbor impact at the end of its travel. In order to avoid unreasonably tall counterweight stacks at high capacity line sets, arbors may employ more than one counterweight stack. Such arbors use multiple-width top and bottom plates with a tie bar and pair of connecting rods provided at each counterweight stack. Counterweight rigging systems use either "tracked" or "wire-guided" arbor guide systems. The tracks or wire guides limit lateral movement of the arbors during arbor travel. Wire-guided systems have lower capacities and are not in common use. In addition to guiding the arbors, a tracked counterweight system is provided with "bump stops" at arbor high and low trim that establish the limits of an arbor's travel. A tracked guide system is sometimes referred to as a T-bar wall, as the tracks are commonly made of steel T-sections. Aluminum arbor guide tracks are a relatively recent alternative, often using a J profile, instead of a T profile, to facilitate system installation. Theatrical Carpentry pg. 15

21 FLY SYSTEMS Hoists: Hoists of various types are used in manual automated rigging systems. The terms hoist and winch are often used interchangeably in theater jargon. Hoists are generally assumed to be motorized unless "manual" is used as a descriptor. "Manual hoists", or "hand winches", are typically composed of a drum, gear box, and crank (operating handle). A worm gear is commonly used to provide mechanical advantage as the crank is turned, which coils a single line around a smooth or helically-grooved drum. The drum line is connected to the lift lines with a "clew", triangular plate with holes used for line terminations. From the clew, the lift lines run over a head block and loft blocks down to a batten. The clew may be wire guided to limit lateral play. Drill operated hand winches permit the handle to be removed so that an electric drill may operate the hoist. Drum hoists: are typically composed of an electric brake motor and multi-line helically-grooved drum. Helical drums are preferable to smooth drums for cable longevity and the precise and repeatable control of travel. Drum hoists are used for motor-assist, engaging an operating line, and dead-haul, engaging the lift lines, applications. A dead-haul drum hoist uses the single drum to support all the lift lines running from the head block of a line set. The lift lines neatly wrap and unwrap in a side-by-side arrangement on the drum as it is spun by the motor. As a lift line coils and uncoils from the drum of a drum hoist, its fleet angle (angle of a line between drum and sheave) changes. Excessive fleet angles (e.g. greater than 1 1/2 or 2 degrees) cause unpredictable line behavior and can damage lines, blocks, and drums. As a result, fleet angles limit how close a dead-haul drum hoist can be mounted to the head block (usually about 10 feet). A" moving drum hoist" is a variation on the traditional drum hoist. Moving drum hoists effectively eliminate the fleet angle between drum and block by shifting the drum along its axis as it spins. The amount of shift per drum revolution is equal to the pitch of the drum's helical groove. With the fleet angle problem resolved, moving drum hoists can combine drum and head block into a single, relatively compact, unit for mounting to fly loft structure, with a corresponding reduction of installation cost. Theatrical Carpentry pg. 16

22 FLY SYSTEMS Line shaft hoist: are typically composed of an electric brake motor, line shaft (drive shaft) and evenly spaced single-line drums aligned above the batten pick points. By placing an individual drum over each pick point, line shaft sets have the advantage, over drum sets, of eliminating the need for blocks. To avoid lateral drift of the batten as the lift lines pay out of the grooved drums, the helical groove orientation on the drums of the line shaft may be alternated between drums to balance competing fleet angles. However the elimination of drift may be compromised by limited batten travel. "Yo-yo, or pile-up hoists" are typically line shaft hoists that use yo-yo type devices instead of drums. Yo-yo hoists are typically used where lighter loads are imposed (e.g. for operating an Austrian puff curtain). Because yo-yos lines pile-up (coil), the velocity and travel of the lines are relatively hard to accurately control. Point hoists: also known as "spot line winches", control a single lift line and are commonly used for automated spot rigging or flying rigs. A point hoist may operate in solitude, or in unison with other point hoists to comprise a line set. Point hoists using wire rope (GAC) are common, and steel band point hoists are also used. operate at relatively high speeds. Wire rope spot line winches may pay out to the side, for use with a loft block, so that only the block need be spotted above the pick point (instead of the entire winch). Chain hoists: more commonly referred to as "chain motors", are the most common form of point hoist, especially with touring musical shows (e.g. rock-and-roll shows), but are relatively slow. Chain motors can be mounted at the grid to hoist a load from above, or mounted at the load to "climb" towards the grid. Theatrical Carpentry pg. 17

23 FLY SYSTEMS Infrastructure: "Fly system infrastructure" consists of the relatively permanent load-bearing and loadtransferring structures of a stage house. The infrastructure, generally fabricated of structural steel members, is sized by a structural engineer during the design of a new theatre, or theatre renovation. Rigging system infrastructure ultimately limits a fly system's capacity. Fly loft: fly tower or fly space, is the large volume above the stage into which line set battens are flown, along with whatever load they may be carrying. In a full size fly space, the tower is preferably at least 2.5 times as tall as the proscenium, to allow a full-height set piece to be stored completely out of view of the audience while providing adequate travel distance for standard (single-purchase) counterweight arbors. Grid deck: gridiron deck, or grid", is a permeable working surface present at the top of many fly lofts that is used to support and provide access to many of a rigging system's components. Though originally constructed of wood, down-facing three-inch steel channels with three-inch gaps became the prevalent grid decking in the 20th century. Today, large-opening heavy-duty steel bar grating is most common in new theatres. The grid deck surface is usually rated to support live loads as well as all anticipated dead-hung equipment and hemp and motorized (e.g. chain hoist) spot rigging. Its permeability facilitates the mounting of equipment and the passing of lift lines and electrical cables. Spot rigging is not feasible without a grid. The grid deck allows access to the "head block beam" and "loft block beams" of counterweight systems. Spanning from the proscenium wall to the upstage wall, these beams support the dead and live loads of a fly system. As per their names, counterweight system head blocks and loft blocks may be directly mounted to these beams. The head block beam is situated directly above the loading gallery. The loft block beams are spaced to match the "pick points" of the lift lines suspending the battens. The loft block beams may also be used to suspend the grid deck support structure. A grid deck is indispensable in professional and touring theatres, and desirable in all theatres with a fly tower, providing invaluable access and flexibility to fly systems. However, due to height limitations, not all fly towers are equipped with a grid. Transverse catwalks are Theatrical Carpentry pg. 18

24 FLY SYSTEMS sometimes provided as compensation for the lack of a grid. San Francisco's War Memorial Opera House, not burdened by height limitations, has two grid decks. Rope line (hemp) head block well: channels sit atop the grid deck and are used for mounting hemp system head blocks. They are situated above the pinrail(s) below. Loft block wells: are ten inch gaps between pairs of face-to-face steel channels flush with the grid deck that occur beneath each loft block beam. The loft blocks of a hemp, or grid-mount counterweight, rigging system can mount to the loft block well channels. The loft block wells may also act as clear openings through which the lift lines of under-hung counterweight, or automated, systems may pass. Loading bridge: Specific to a stage house using a counterweight system, the "loading bridge", or "loading gallery", is a catwalk vertically positioned below the headlock beam, and above the fly gallery. The loading bridge is used to add or remove counterweights from arbors. The floor of the loading bridge is also typically used as a storage area for uncommitted counterweights that are available for loading onto counterweight arbors. Stage houses with especially tall fly towers, or double-purchase systems, may have two loading bridges, one stacked over the other to facilitate the loading of relatively tall arbors. Fly gallery: A "fly gallery" is a catwalk running from the proscenium wall to upstage wall to which a pinrail and/or locking rail may be mounted used by the fly crew to operate the fly system. The fly gallery elevation is typically at about proscenium height, providing a good view of the stage and fly loft. Fly galleries may be provided stage left and right, or at just one side. Where provided at both sides of the stage they may be connected by a cross-over catwalk at the upstage wall. It is possible to load arbors ( add or remove counterweights) at the fly gallery, but standard practice is to load arbors at the loading bridge. Theatrical Carpentry pg. 19

25 FLY SYSTEMS Pin rail: A "pin rail", originally a wood beam, is typically a large-diameter round steel tube with vertical through-holes that accept belaying pins used in a hemp rigging system. Depending on the pin rail design, the pins may be removable or permanently fixed to the rail. Pin rails are typically installed permanently at the onstage edge of the fly gallery(ies), extending from the proscenium wall to upstage wall, sometimes in a stacked (rail over rail) arrangement. Mobile pin rails may also be used and are bolted down to the stage deck where needed. Locking rail: A "locking rail" is typically a steel angle or rectangular tube to which the rope locks of a counterweight system are mounted. Locking rails are located on the stage deck and/or fly gallery and typically extend from the proscenium wall to the upstage wall. A stage-level locking rail may be provided with an engaging bar for a portable capstan winch. Arbor pit: "Arbor pits", where provided, are troughs at the stage edge that provide additional vertical travel to a counterweight system's arbors. Providing a counterweight arbor pit can help compensate for height limitations of a fly tower. The trough depth typically ranges from 2 to 10 feet. Shallower pits may be accessible only from above at the stage deck. Deeper pits are sometimes accessible from a trap room or orchestra pit. Operation: Because fly systems involve large amounts of weight, and particularly because the weight is usually suspended above people, there are a number of precautions taken to ensure safety and prevent injuries. Communication, inspection, and loading procedure are a key to the safe operation of a fly system. Except for during performances and some rehearsals, a standard practice in theatre is for the flyman to always call(shout) out a warning before moving a lineset so as to alert personnel (e.g., Theatrical Carpentry pg. 20

26 FLY SYSTEMS rehearsing performers and technicians) who are on the stage. People on stage typically acknowledge the operator's warning by yelling out a confirmation that the warning was heard. A "runaway" is a moving lineset that cannot be safely controlled by its operator. Runaways can occur when the weight on the arbor is not equal to the weight of the batten and its load. Linesets are often intentionally unbalanced to facilitate quick flying in one direction and, in such cases, runaways are more likely to occur. When loading a batten, or arbor in a counterweight system, it is imperative to control the balance of a set. The line set should be balanced before loading begins, then the batten flown in, the set added, and then the counterweight added from the loading bridge. The specific order is important because it keeps the set from being unbalanced in a position where it could run away. When it is batten-heavy (after the set is added, but before the counterweights) the arbor does not have anywhere to run away to as it is already at its grid stop (the upper end of the track). In cases where the set is too tall for the batten to be all the way in, it should be kept as far down as possible. It is always best to add the load in pieces as small as practical and counterweight them one at a time so the system can never get too out of balance. Improper loading procedure is a common cause of accidents in many theaters. Theatrical Carpentry pg. 21

27 SOFTGOODS Curtains: a cloth that fills the stage opening. Generally opaque, usually in a dark or subdued colors, made from heavy cloth. The best are made from velour, as this fabric is best at light absorption and has the lowest reflection. Curtains are usually hung with fullness, or pleating. Pleating may be sewn in, or created by hanging a long curtain on a shorter pipe, with the fullness tied in. Fifty percent (50%) fullness is common, meaning the curtain when stretched is half again as long as when tied on the batten. Legs: narrow curtains used as masking at sides of stage to hide wings. Tormentors: furthest downstage legs, the "torms". Used to reduce the size of the proscenium opening. Often hard, with a frame and hard substance beneath a velour covering. Borders: short curtains used to mask the top of the stage, to mask the fly loft. Teaser: furthest downstage border also used to reshape proscenium opening. Teaser is sometimes called the grand drape or the "Valence". Portal: a border and legs combined into a single piece with a large opening Velour: best cloth for curtains, a dull finished knapped fabric, really a form of velvet. Best at light and sound absorption and blocking, but also the heaviest and most expensive fabric for curtains. Theatrical Carpentry pg. 22

28 SOFTGOODS Duvetine: lighter, cheaper substitute, a heavy fabric with brushed rather than woven knap. Looks almost like velour and weighs less, but doesn't work as well. Corduroy: another substitute for velour, also cheaper and lighter weight; works well if it has a thin "wale". However the "wale" gives it a definite directionality. Construction of Curtains: Guillotine Curtain: flies straight up and down. One of the most common curtain riggings. Travelers or draw curtains: split in the middle into two (2) panels and pulled open and shut on tracks, generally with a endless operating line. Usually operated by hand, but may be run with a winch, especially with remote control systems. Braille curtain, or Austrian drape: a curtain raised from the bottom using vertical parallel lift lines. Tab or Tableau curtains: also known as Venetian drapes: rigged similarly to braille curtains, but can be raised in various configurations because each lift line can be individually adjusted. Contour or profile curtains: also known as Venetian drapes: rigged similarly to braille curtains, but can be raised in various configurations because each lift line can be individually adjusted. Theatrical Carpentry pg. 23

29 SOFTGOODS Fullness: Curtains, borders, legs may all be hung stretched flat, or may be hung with fullness. Fullness is a gathering of the material of the soft goods to make it thicker and make it disappear in light even more. Looks more attractive and finished than when hung flat. Fullness is expressed in percentage of fabric folded back on itself, or how much longer material is than pipe length it takes up. Therefore: a curtain half again as long as the pipe it is hung on with the excess distributed as gathers or pleats, has 50% fullness. If it is twice the length of its batten, it has 100% fullness. Fullness can be sewn in using any desired pleating system. Gather Z-fold Box Sewn fullness is easier to put up, only need to stretch the top out and tie to batten. Also, works well with traveller system; top can be pulled flat by the carriers but the fullness will stay evenly distributed. However, if fullness is sewn in, can't hang piece without fullness. An alternative: use tied fullness. In this system, curtains are sewn flat but made longer than pipe. Piece is tied on with gathers. Tied in fullness will not work well with travellers, as the carriers pull the fullness out as they extend. You CAN tie a sort of pinched pleat in by tying two grommets to each carrier, but that is all, and it doesn't work as well as a sewn fullness. Other Softgoods Scrims: curtain made of an open weave fabric becomes transparent when lit from behind, but which appears opaque when lit from the front. Theatrical Carpentry pg. 24